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Summary: In chronic lymphocytic leukaemia (CLL) the efficacy of SARS‐CoV‐2 vaccination remains unclear as most studies have focused on humoral responses. Here we comprehensively examined humoral and cellular responses to vaccine in CLL patients. Seroconversion was observed in 55.2% of CLL with lower rate and antibody titres in treated patients. T‐cell responses were detected in a significant fraction of patients. CD4+ and CD8+ frequencies were significantly increased independent of serology with higher levels of CD4+ cells in patients under a Bruton tyrosine kinase (BTK) or a B‐cell lymphoma 2 (BCL‐2) inhibitor. Vaccination skewed CD8+ cells towards a highly cytotoxic phenotype, more pronounced in seroconverted patients. A high proportion of patients showed spike‐specific CD4+ and CD8+ cells producing interferon gamma (IFNγ) and tumour necrosis factor alpha (TNFα). Patients under a BTK inhibitor showed increased production of IFNγ and TNFα by CD4+ cells. Vaccination induced a Th1 polarization reverting the Th2 CLL T‐cell profile in the majority of patients with lower IL‐4 production in untreated and BTK‐inhibitor‐treated patients. Such robust T‐cell responses may have contributed to remarkable protection against hospitalization and death in a cohort of 540 patients. Combining T‐cell metrics with seroprevalence may yield a more accurate measure of population immunity in CLL, providing consequential insights for public health. [ABSTRACT FROM AUTHOR]

NOTCH1 mutations and deregulated signal have been commonly found in chronic lymphocytic leukemia (CLL) patients. Whereas the impact of NOTCH1 mutations on clinical course of CLL has been widely studied, the prognostic role of NOTCH1 activation in CLL remains to be defined. Here, we analyzed the activation of NOTCH1/NOTCH2 (ICN1/ICN2) and the expression of JAGGED1 (JAG1) in 163 CLL patients and evaluated their impact on TTFT (Time To First Treatment) and OS (Overall Survival). NOTCH1 activation (ICN1+) was found in 120/163 (73.6%) patients. Among them, 63 (52.5%) were NOTCH1 mutated (ICN1+/mutated) and 57 (47.5%) were NOTCH1 wild type (ICN1+/WT). ICN1+ patients had a significant reduction of TTFT compared to ICN1-negative (ICN1−). In the absence of NOTCH1 mutations, we found that the ICN1+/WT group had a significantly reduced TTFT compared to ICN1− patients. The analysis of IGHV mutational status showed that the distribution of the mutated/unmutated IGHV pattern was similar in ICN1+/WT and ICN1− patients. Additionally, TTFT was significantly reduced in ICN1+/ICN2+ and ICN1+/JAG1+ patients compared to ICN1−/ICN2− and ICN1−/JAG1− groups. Our data revealed for the first time that NOTCH1 activation is a negative prognosticator in CLL and is not correlated to NOTCH1 and IGHV mutational status. Activation of NOTCH2 and JAGGED1 expression might also influence clinical outcomes in this group, indicating the need for further dedicated studies. The evaluation of different NOTCH network components might represent a new approach to refine CLL risk stratification. [ABSTRACT FROM AUTHOR]

Nucleophosmin (NPM1) mutations occurring in acute myeloid leukemia (AML) (about 50 so far identified) cluster almost exclusively in exon 12 and lead to common changes at the NPM1 mutants C-terminus, i.e., loss of tryptophans 288 and 290 (or 290 alone) and creation of a new nuclear export signal (NES), at the bases of exportin-1(XPO1)-mediated aberrant cytoplasmic NPM1. Immunohistochemistry (IHC) detects cytoplasmic NPM1 and is predictive of the molecular alteration. Besides IHC and molecular sequencing, Western blotting (WB) with anti-NPM1 mutant specific antibodies is another approach to identify NPM1-mutated AML. Here, we show that among 382 AML cases with NPM1 exon 12 mutations, one was not recognized by WB, and describe the discovery of a novel combination of two mutations involving exon 12. This appeared as a conventional mutation A with the known TCTG nucleotides insertion/duplication accompanied by a second event (i.e., an 8-nucleotide deletion occurring 15 nucleotides downstream of the TCTG insertion), resulting in a new C-terminal protein sequence. Strikingly, the sequence included a functional NES ensuring cytoplasmic relocation of the new mutant supporting the role of cytoplasmic NPM1 as critical in AML leukemogenesis. [ABSTRACT FROM AUTHOR]

Skeletal muscle undergoes regeneration generally after an injury and in some cases it may mimic a malignant process. We observed these aspects in association with abdominal wall endometriosis and as no similar conditions were found in the literature this prompted us to study the main clinicopathologic and immunohistochemical profile of this phenomenon. Thirteen cases of abdominal wall endometriosis were retrieved from the files of our Institute. All original slides were reviewed to reveal the presence of skeletal muscle and 8 cases were enrolled for morphologic and immunohistochemical studies as follows: vimentin, desmin, myoglobin, myogenin, myoD1, CD56, S100, and p21. Histologically, in 4 of the 8 cases in the skeletal muscle adjacent to the endometriotic foci there was a proliferation of round cells with the typical appearance of maturing myoblasts. More peripherally, myotubes and early myocytes were present. This proliferation was florid in 1 case and focal in 3 cases. At immunohistochemical investigation, the less differentiated cells reacted with vimentin, desmin, S100, CD56, myoD1, and myogenin but not with myoglobin or p21. On the contrary, intermediately differentiated cells showed a progressive loss of vimentin, CD56, and myoD1 whereas they were positive for desmin, S100, myogenin, myoglobin, and p21. Terminally differentiated cells reacted only with desmin and myoglobin. This peculiar immunohistochemical profile was consistent with the immunophenotype of maturing myoblasts, confirmed the regenerative nature of the phenomenon and allowed differential diagnosis with other proliferations sharing a similar morphology. The expression of early differentiation markers was greatest in the islands of cells nearest to endometriosis, whereas in the more distant areas the markers of late differentiation prevailed. This gradient of expression suggests that muscle cells are stimulated by growth factors or other signals produced by the cycling endometrioid foci. In conclusion, we report a hitherto undescribed entity that may mimic a malignant process, especially when the reaction is florid or when endometriotic glands and stroma are not clearly evident, as during the examination of small biopsies, frozen sections, or cytology samples. Therefore, although the histologic diagnosis of endometriosis is usually straightforward, pathologists should be aware of the concomitant regenerative effects on skeletal muscle, which may represent a possible diagnostic pitfall.

Primary signet-ring cell carcinoma of the urinary bladder is a rare histologic variant of adenocarcinoma. Generally, this neoplasm occurs in middle age and the clinical presentation does not differ from the most frequent transitional cell carcinomas. The prognosis is frequently poor as at diagnosis it is often in an advanced phase. It is essential to distinguish this carcinoma from metastases, as different therapeutic strategies are often necessary. We present 5 cases of primary signet-ring cell carcinoma of the urinary bladder and we used a panel of histochemical and immunohistochemical markers for differential diagnosis from secondary carcinoma in an attempt to elucidate the histogenetic derivation of this neoplasia.